Recording system with provision for fast or slow reproduction



Feb. 16, 1965 SHIRO OKAMURA 3,170,031

RECORDING SYSTEM WITH PROVISION FOR FAST OR SLOW REPRODUCTION OriginalFiled Nov. 2, 1960 2 Sheets-Sheet. l

Tlil- X 7 T131..-

l N V E N TO R 1554/40 Omvmuen ATTOR Y Feb. 16, 1965 SHIRO OKAMURA3,170,031

RECORDING SYSTEM WITH PROVISION FOR FAST OR SLOW REPRODUCTION OriginalFiled Nov. 2, 1960 2 Sheets-Sheet. 2

I N V E N TO R .S'H/eo 010907009 ATTORN Y l2 I2 754 E- A FEAME 569/776 2[Amen l) Cam/EH54 EMm/mk [Eff/V54 tozvvfkme United States Patent3,170,031 RECORDING SYSTEM WITH PROVISION FQR FAST 0R SLOW REPRODUCTIONShiro Okarnura, 26 Z-chome, Shiroganedaimachi,

, Minatoka, Tokyo, Japan Continuation of application Ser. No. 66,770,Nov. 2, 1960. This application Dec. 27, 1963, Ser. No. 338,277 12Claims. (Cl. 178--6.6)

This invention relates to a signal treating system utilizinginterpolation of the time pattern of information, and more particularly,it relates to a system for frame frequency conversion, for signalbandwidth compression and also for selectively varying slow and quickmotion processes in television. This application is a continuation of mycopending application Serial No. 66,770, filed November 2, 1960, nowabandoned.

One object of the present invention is to provide a novel transmissionsystem whereby an arbitrary conversion between two signals which differin scanning frequency is feasible.

Another object of the present invention is to provide a novel signaltreating system which permits band compression without noticeableflicker, distortion or a reduction in definition.

Still another object of the present invention is to provide a novelvideo signal treating system which makes it possible arbitrarily to varythe time velocity of a television picture being transmitted, i.e., toproduce slow motion or quick motion, for example, of the picture duringthe normal time of transmission. The invention is not limited however touse with a video signal but may find application with other types ofperiodical signals comprising sub-periods similar to the horizontal linesubperiods of the video signal.

According to one aspect of the invention, there is provided a signaltreating system having means for recording video signals along aplurality of recorded tracks arranged one after another, the tracksbeing similar except for variation due to elapsing time, means forpermitting interpolation between adjacent tracks, and means forreproducing the video signals from the recorded tracks.

According to another aspect of the invention there is provided atelevision system having means for recording a video signal, means forrecording the tracks in parallel arrangement one after another, meansfor making adjacent tracks substantially similar except for variationdue to elapsing time, means permitting interpolation between saidadjacent tracks, and means for reproducing the video signal having anarbitrary repeating rate from the recorded tracks.

According to another aspect of the invention there is provided a signaltreating system having means for recording a video signal in paralleltracks arranged one after another, adjacent tracks being similar exceptfor variation due to the time elapsing, means permitting interpolationbetween the adjacent tracks, means for reproducing a substantiallyflickerless video signal having a different field frequency from that ofthe recording, means for transmitting the said reproduced video signal,and means for again recording the said transmitted video signal inaccordance with the recording procedure, and means for reproducing avideo signal of still another frequency.

According to another aspect of the present invention there is provided atelevision system having means for reproducing a signal which has adifferent time elapsing rate from the rate at which the signal isrecorded as above described, whereby the effect of slow motion, quickmotion and stationary memory of the picture can be arbitrarilyintroduced into the picture of normal time duration.

According to still another aspect of the present invention there isprovided a video tape recorder in which the adjacent parallel trackshave approximately the same information except for the variation due totime elapsing and in which interpolation may be performed betweenadjacent tracks.

All of the objects, features and advantages of this invention and themanner of attaining them will become a more apparent and the inventionitself will be best understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theaccompanying drawings, in which FIG. 1 illustrates an example of arecording medium having tracks recorded thereon according to theinvention; FIG; 2 is a view illustrating the recorded signal intensitiesof selected track segments taken transversely of the tracks;

FIGS. 3A and 3B show respectively the elevation and the side view of areproducing magnetic head with respect to the recorded tracks; 1

FIGS. 4 and 5 are simplified diagrams of recording and reproducingapparatus according to the invention;

FIG. 6 is a simplified diagram of another embodiment of the recordingand reproducing apparatus of the invention.

FIGS. 7A and 7B show still another example of a video tape recorder inaccordance with the invention, the elevation being shown in FIG. 7A andthe sideview' in FIG. 713.

FIG. 8 shows one recorded pattern according to the invention which isproduced by means of the apparatus shown in FIGS. 7A and 7B;

FIG. 9 shows another form of the recorded pattern according to theinvention;

FIG. 10 is a block diagram of a band compression system according to theinvention, and

FIG. 11 shows recorded patterns which are employed for band compressionof the video signal according to the invention.

In FIG. 1 there is shown a magnetic storage recording medium in the formof a magnetic tape 1. On this tape there is recorded a plurality oftracks adjacent and parallel to one another, each track comprising aplurality of recorded track segments I, 2 5 0 9 and 516 which togethermake one picture frame. Each track segment corresponds to one horizontalline signal of one frame of a video signal. For simplicity, interlacingis not shown in FIG. 1. Each corresponding track segment in each trackis arranged exactly at the same distance from the boundaries or borderlines 11 and 12 as shown. These border lines may coincide with thevertical blanking portion of the video signal. It is to be noted thatthis arrangement facilitates switching from one border to the other. Therecorded track segments overlap at their edges as shown in FIG. 2 by theletters p and q, which designate the recorded signal intensities foradjacent tracks 5 and 6, so that the reproduced output may besubstantially constant, rather than becoming null even if thereproducing head may not scan the tracks in alignment therewith. Thevertical height of the recorded signal intensities p and q may alsoindicate the intensity of the reproduced signal, and the horizontallength of the scan corresponds to the distance lateral to the tracks 5,6 and so on. It is also to be noted that this arrangement allowseconomic utilization of the area of the recording medium and also animprovement in the accuracy of the translation velocity of the mediumbecause the information always varies gradually along the tape length.

This constancy of the reproduced signal can also be obtained by means ofa reproducing head 4 having a rather broad width compared with thedistance between the tracks as shown in FIG. 3. FIG. 3A shows theelevation of the reproducing head and FIG. 3B shows the side viewthereof. Adjacent recorded tracks are indicated by the numerals 5 and 6in FIG. 3A. In any case, the overall response may be substantiallyconstant during the recording and reproducing procedure. This constancyof the reproduced signal, however, is not absolutely necessary. Someexisting variation of the overall response may be cancelled by one ofthe known techniques, such as for example, limiting, controlling thegain, or making use of feedback circuits.

As described above, each recorded pattern of the video signal across thewidth of the tape produces continuous scanning as a function of time, asdistinguished from the recording process of the prior art. Thus, forexample, the dashed line xx in FIG. 1 indicates a scanning at one thirdof the original scanning rate and the reproduced signal will thereforehave a frame frequency one third that of the original or recorded rate.In accordance with the principles of the invention, the frame frequencyof the reproduced signal may be varied over a wide range by choosing thespeed of the reproducing head so that it has a lateral component ofvelocity across the tracks.

FIG. 4 is a simplified drawing of apparatus for performing the recordingand reproducing as discussed above. In this figure two magnetic heads 13and 14 on a rotating drum l5 scan the magnetic tape 1 as it istranslated from left to right, thus yielding the recorded tracksindicated by the numeral 22. The period of revolution of the drumcorresponds to the frame period or its multiples of the video signal soas to form the pattern as shown in FIG. 1. The recording and/orreproducing procedure contains the aforesaid overlapping relationship ofadjacent track segments, as shown in FIG. 2. The two heads 13 and 14 maybe switched or not switched as appropriate. The reproducing head drum 23containing two heads and may be rotated at different speeds to yield avideo signal of an arbitrary reproducing frame frequency different fromthat of the recording frame frequency. The magnetic tape 1 must, ofcourse, be curved as shown to conform to the curvature of the rotatingdrums 15 and 23.

FIG. 5 shows another example of apparatus utilized in the presentinvention. A magnetic drum 16 is translated relatively from left toright and a recording head 17 rotating at n revolutions per second and areproducing head 18 rotating at n revolutions per second are provided.The recorded tracks are indicated by numeral 21. The drum 16 may also berotated if desired. This drum 16 has a vertical blanking portion orportions 26, in the case of FIG. 1, since the rotating speed it ischosen to be equal to the frame frequency or a fraction thereof. Thedrum 16 can be scanned by the reproducing head 13 at an arbitrary numberof revolutions it as described above which is designed to produceoverlapping of adjacent tracks, as shown in FIG. 2. Thus the apparatusshown in FIG. 5 operates also as a frame frequency converter into anydesired frame frequency without any flicker or reduction in definition.As a practical matter, the drum 16 can not be made as long as desired,so that switching is necessary to switch the translating direction forcontinuous operation. The apparatus shown in FIG. 4, however, may employan endless tape.

FIG. 6 shows another endless memory device in which a magnetic pulley 27rotates slowly. The magnetic rim -27 of the pulley is traversed forrecording by means of a recording head 17 and for reproduction by meansof a reproducing head 18, both of which are rotated.

FIGS. 7A and 7B illustrate video tape recording equipment which is knownas the single head VTR system. FIG. 7A shows the elevation and FIG. 7Bthe sideview of elements of this system. The magnetic tape 8 is woundand transported spirally around two coaxial cylinders '7 which areslightly separated as indicated by the dashed lines. A head 9, rotatingabout an axis 10, scans the inside of the tape 8. The recorded trackpattern produced by this apparatus is shown in FIG. 8. The inclinationangle 0 of the track with respect to the longitudinal axis of the tape,can be varied by the design of the apparatus. It is therefore possibleby the suitable design t record the consecutive frames or fields alongadjacent oblique tracks, one after another, as shown in FIG. 8 or FIG.9. The discrete track segments indicated by the numerals I, Q, g to 5 6in FIG. 8 indicate the sequential number of the recorded horizontal linesignals in a picture frame. In FIG. 9, numerals I, 2, 5 to indicate onefield of a frame, and numerals Q3, 25?, T5 to 5T6 indicate anotherfield, these two fields together comprising one frame. As shown, thediscrete track segments of one track lie directly alongside the discretetrack segments of adjacent tracks so as to form rows of discretesegments which are perpendicular to the direction of the tracks.Furthermore, the tracks of the recorded pattern are so positioned thatthe segments of the dilferent tracks which represent corresponding linesof the different picture frames occupy corresponding positions withrespect to the boundaries or edges 11-12 of the tape. By proper choiceof the tape translation velocity and the inclination angle 0, it ispossible to provide the recorded pattern with the discrete segmentspositioned as described above.

FIG. 8 shows the case in which one frame is recorded in an obliquedirection on each track, and FIG. 9 illustrates a pattern wherein eachtrack represents one eld and in which the effect of interlacing appears.In both cases of FIGS. 8 and 9 it will be apparent that adjacentrecorded tracks have approximately the same information, so that if theeffect of interpolation as shown in FIG. 2 is introduced into thissystem, the application is similar. Such recording patterns also enableeconomic use of the tape area and permit irregular tape translationvelocity. The tape may be endless or not, as desired, depending on theapplication. Other suitable devices may be utilized in the presentinvention providing they permit the recorded pattern of the aforesaidnature.

The frame frequency converting system described above can also beemployed to provide picture frequency conversion of motion pictures. Forexample, the picture frequency of 16 frames per second can easily beconverted to 24 frames per second via the video signal as shown above.In such a case a television camera having a frame frequency of 24produces a video signal which is recorded and reproduced according tothe present invention. The reproduced picture of 24 pictures per secondis again filmed by a corresponding synchronized camera.

Of course a video signal of different frame frequency from the originalfilm can be easily produced and may be transmitted. For example, thefrequency of 24 pictures per second can be comfortably transformed to avideo signal frequency of 30 frames per second.

The frame frequency converting system according to the present inventioncan also be employed to produce band width compression, which isimportant for long range television transmission.

FIG. 10 is a simplifield block diagram of this system according to theinvention. In this figure, a television camera 23 produces a picturehaving a frame frequency of n, which is converted to a frame frequencyof n by means of a frame converter 29, as described above. The convertedvideo signal modulates a transmitter 34 and the modulated wave ispropagated from an antenna 31 or transmitted via a cable. The receivedsignal from the antenna or the cable is detected and amplified by areceiver 35 and the frame frequency of n is again converted to n orother frequency by means of a second frame converter 33. If thefrequency n is chosen to be substantially smaller than the frequency 12,the video band width is decreased by the factor n'/n. This bandcompression system has the advantage over the prior art that thereproduced picture is always flickerless and the definition is excellentso long as the motion of the tele vised object is not too rapid.

FIG. 11 shows the patterns of succeeding converting procedures at thetransmitting and receiving stations 34- and 35 respectively. Theinclination of the hatched lines indicates the video information, onehorizontal line of which is assumed to be unchanged throughout-one frameperiod for simplicity. Only nine lines are shown in one frame forsimplicity. Thus, tracks'l-l, 2-2, etc., correspond to the succeedingframe information on the pattern (a) which shows the first recordingprocedure. The envelope of each group of hatched lines forms theinformation parallelograms for each line, which shows the gradual,continuous change along the succeeding frame. The recorded pattern (a)is scanned along lines AA, BB, etc., which show a reproduction scanningof half of the recording frame frequency, i.e., n' n/ 2. duced signal isobtained at the interception of lines AA, BB, etc., with theinformationparallelograms occurring Where the intercepting areascontribute to theinclination of the reproduced parallelograms as shown in 8). The

pattern (5) is obtained by the procedure above described on reproductionfrom the pattern (a). This is the transmitted and re-recorded signal atthe frame converter 33 in FIG. 10. The re-recordin'g procedure is alsointerpolatable as in the case of the frame converter 29. The pattern (5)is again reproduced at the frame frequency of n=2n along the scanningpath AA, BB, etcfin (,8). The reproduced pattern is shown at ('y) inFIG. '11. The drawing is made according to the procedure described abovein conjunction withthe converting procedure from the pattern (or) to(B). It is to be observed that the pattern (7) is quite similar tothepattern t). The similarity is dependent upon the velocity and linearityof movement of the original televised scene.

. The converted framefrequ'ency maybe any fraction of the original framefrequency. It is not limited to division by an integer. -The convertedframe frequency may be varied if the atmospheric conditions so require.The frame frequency can be continuously varied with suitablesynchronizing means, such as a vertical synchronizing pulse or asuitable pilot wave, by which means the receiver frame converteroperates synchronously so as to form the pattern as shown in FIG. 11.Thus, the converted narrow 'band signal is transmitted on a carrier.wave of narrow band width, which permits long range transmission. Noflicker can be observed (as is seen in the narrow band transmissionframe down system of the prior art. Of course, the received signal ofthe prior art'frame down system can be converted into a continuouspicture according tothe present invention. r

Another important application of the present invention is in theproduction of slow and quickmotion of television pictures. As describedabove, the recorded track, according to the present invention, providescontinuity of scan for the elapsing time Thus, for example, the recordedtrackshown in FIG. 4 may be reproduced at an arbitrary tape velocity, sothat slow motion, quick motion and standstill effect of a scene may beobtained without flicker.

If the reproduction takes place immediately after recording, and if thevelocity of the tape or other medium relative to the scanning head isvariable, slow or quick motion is arbitrarily introduced into thetransmitting picture. This effect is considered as an arbitraryvariation of the time axis of the'phenomena which is never considered intelevision techniques because of the limitation in the prior art. Forexample, during a televised picture of a sports program, the scene maybe suddenly stopped, or moved, or changed to slow motion or to quickmotion, or even reversal of motion is possible. This is a new effect intelevision casting.

Such effects are performed by varying the relative dis-;

placement between the recording and reproducing head Thereproassemblies. lf the distance between the recording and reproducinghead becomes larger, the quick motion effect is introduced. If thedistance becomes smaller, the

slow motion effect is obtained. The standstill is the 'extreme of slowmotion, and this is obtained by nulling the relative velocity betweenthe tape and the reproducing head assembly. If the reproducing headassembly is moved faster than the tape velocity in a direction oppositeto the direction of the recording assembly, the time elapsing isobviously reversed. For continuous picture transmission, the slow motionmust be followed by quick motion and vice versa to return to the regularprogram The apparatus shown in FIG. 6 is useful in thisapplication.

For relatively short time treatment, the apparatus shown in FIG. 5 ispreferable. The magnetic cylinder 16 is rotated at a velocity of, forexample, frame frequency regular program, into which delaying means maybe added if necessary.

Other apparatus may be employed for suchtreatment. For example theapparatus shown in FIG. 7 is very useful in that a tape of narrow Widthmay be employed.

In theforegoing description, the storage mediums have been shown in theform of a tape, drum, and pulley.

Any other suitable storage medium can of course be employed which may betranslated relative. to the locus of the scanning means. been describedwith'particular reference to a video signal, it is to be understood thatit can be employed with any periodical signal comprising a plurality ofsub-periods such as the horizontal periods of the video signal.

While the. foregoing description sets forth the principles of theinvention in connection with specific apparatus,

it is to be understoodthat the description is made only- ,by way ofexample and not as a limitation of thescope of the invention as setforth in the objects thereof and" in the accompanying claims. i

What is claimed is: i

1. A signal recording and reproducing system'com prising a magneticstorage medium, means-forreceiving a periodical signal, means forrecording said periodical signal on said magnetic storage mediumwith'adjacent periods of said signal being recordedon adjacent tracksacross said magnetic storage surface, said tracks being disposedsubtantially parallel'to each other and being in in lateral alignmentclosely adjacent to each other,'and 55' means for reproducing saidsignals recorded on said magnetic storage surface, said reproducingmeans being adapted to move in a path having a substantial and lateralcomponent of velocity across said recorded tracks to speed up or retardsaid reproduced signals with respect to said recorded signals.

2. The combination defined in claim 1 in which said periodical signalscomprise television signals and in which said reproducing means producefast or slow motion effects in the reproduced television signals.

3. The combination defined in claim 1 in which said tracks are recordedin laterally overlapping relation to each other to permit smoothinterpolation from one trackto another.

4. A television transmission system comprising a television signalsource adapted to produce periodical television output signals, a firstsignal recording and reproducing system as defined in claim 1 coupled'to the output of said television signal source, said first signalrecording and reproducing system being adapted to retard said reproducedsignals with respect to said recorded signals, a

Also, while the invention has.

television transmitter coupled to the output of said first signalrecording and reproducing system, a television receiver adapted toreceive the transmission of said television transmitter, a second signalrecording and reproducing system as defined in claim 1 coupled to theoutput of said television receiver, said second signal recording andreproducing system being adapted to speed up its reproduced signal withrespect to its recorded signal, and television signal display meanscoupled to the output of said second signal recording and reproducingsystem.

5. In a signal treating system, the improvement comprising means forreceiving periodical signals, means for recording said periodicalsignals on a magnetic storage medium with adjacent periods of saidsignal being recorded on-adjacent tracks across said magnetic storagesurface, said tracks being disposed substantially parallel to eachother, and reproducing means adapted to move in a path having asubstantial and lateral component of velocity across said recordedtracks to speed up or retard the reproduced signals with respect to therecorded signals.

6. The combination defined in claim 5 in which'said tracks are recordedin laterally overlapping relation to each other to permit smoothinterpolation from one track to another.

7. A television transmission system comprising a television signalsource adapted to produce periodical television output signals, a firstsignal treating system as defined in claim 5 coupled to the output ofsaid television signal source, said first signal recording andreproducing system being adapted toretard said reproduced signals withrespect to said recorded signals, a television transmitter coupled tothe output of said first signal recording and reproducing system, atelevision receiver adapted to receive the transmission of saidtelevision transmitter, a second signal treating system as defined inclaim 5 coupled to the output of said television receiver, and saidsecond signal treating system being adapted to speed up its reproducedsignal with respect to its recorded signal.

8. In a system for recording and reproducing periodical signalscomprising a series of recurring periods each of which contains aplurality of recurring sub-periods, the improvement comprising means forreceiving said periodical signals, means for recording said periodicalsignals on a magnetic storage surface with sequential periods of saidsignal being recorded on adjacent tracks across said magnetic storagesurface, and reproducing means adapted'to move in a path having alateral component of velocity across said recorded tracks to speed up orretard the reproduced signals with respect to the recorded signals.

9. The combination defined in claim 8 wherein said periodical signal isan interlaced television signal com- 8 prising a plurality of recurringframes each containing two recurring interlaced fields.

10. The combination defined in claim 8 in which said traces are disposedsubstantially parallel to each other and in which said tracksarerecorded in laterally overlapping relation to each other to permitsmooth interpolation from one track to another.

11. A signal recording system for recording on a storage medium havingparallel boundaries a periodical signal having a plurality of periodseach including a plurality of sub-periods comprising, recordingtransducer means, and means for moving said transducer means relative toand in close proximity to said storage medium to record said signal onsaid storage medium in the form of substantially parallel tracks havingtheir ends at said boundaries, the relative speed between saidtransducer means and said storage medium being selected so that thelength of each of said recorded tracks corresponds to at least one ofsaid periods, each of said tracks comprising a plurality of discretesegments each of which corresponds to one of said sub-periods of saidsignal, said segments of any given track being positioned directlyalongside the segments of adjacent tracks so as to form rows of segmentswhich are perpendicular to the direction of said tracks, the segments inany given row further being in juxtaposed relationship with the segmentsin said row adjacent thereto, and said tracks being so positioned onsaid medium that the segments of the different tracks which representcorresponding sub-periods of the difierent periods of said signal occupycorresponding positions with respect to said boundaries of said medium.

12. In a signal recording system for recording by means of a recordinghead a periodical signal having a plurality of periods each including aplurality of sub-periods, a signal storage medium for storing saidsignal applied thereto, said signal being recorded thereon in the formof substantially parallel tracks having their ends at said boundaries,the length of each of said tracks corresponding to at least one of saidperiods, each of said tracks comprising a plurality of discrete segmentseach of which corresponds to one of said sub-periods of said signal,said segments of any given track being positioned directly alongside thesegments of adjacent tracks so as to form rows of segments which areperpendicular to the direction of said tracks, the segments in any givenrow further being in juxtaposed relationship with the segments in saidrow adjacent thereto, and said tracks being so positioned on said mediumthat the segments of the ditferent tracks which represent correspondingsub-periods of the different periods of said signal occupy correspondingpositions with respect to said boundaries of said medium.

No references cited. DAVID G. REDINBAUGH, Primary Examiner.

8. IN A SYSTEM FOR RECORDING AND REPRODUCING PERIODICAL SIGNALSCOMPRISING A SERIES OF RECURRING PERIODS EACH OF WHICH CONTAINS APLURALITY OF RECURRING SUB-PESRIODS, THE IMPROVEMENT COMPRISING MEANSFOR RECEIVING SAID PERIODICAL SIGNALS, MEANS FOR RECORDING SAIDPERIODICAL SIGNALS ON A MAGNETIC STORAGE SURFACE WITH SEQUENTIAL PERIODSOF SAID SIGNAL BEING RECORDED ON ADJACENT TRACKS ACROSS SAID MAGNETICSTORAGE SURFACE, AND REPRODUCING MEANS ADAPTED TO MOVE IN A PATH HAVINGA LATERAL COMPONENT OF VELOCITY ACROSS SAID RECORDED TRACKS TO SPEED UPOR RETARD THE REPRODUCED SIGNALS WITH RESPECT TO THE RECORDED SIGNALS.